21773397 has 4 divisors (see below), whose sum is σ = 29031200. Its totient is φ = 14515596.

The previous prime is 21773383. The next prime is 21773399. The reversal of 21773397 is 79337712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21773397 - 2⁶ = 21773333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21773399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3628897 + ... + 3628902.

It is an arithmetic number, because the mean of its divisors is an integer number (7257800).

Almost surely, 2^21773397 is an apocalyptic number.

It is an amenable number.

21773397 is a deficient number, since it is larger than the sum of its proper divisors (7257803).

21773397 is an equidigital number, since it uses as much as digits as its factorization.

21773397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7257802.

The product of its digits is 55566, while the sum is 39.

The square root of 21773397 is about 4666.1972740123. The cubic root of 21773397 is about 279.2385647244.

The spelling of 21773397 in words is "twenty-one million, seven hundred seventy-three thousand, three hundred ninety-seven".